Card data is information tied to a payment card, such as the cardholder name, primary account number (PAN), expiry date, and sometimes partial billing details or transaction tokens. If exposed, it can increase fraud risk, help attackers verify stolen identity details, or support phishing and account takeover attempts.
In cyber security, card data matters because even fragments can be useful when combined with other leaked records. Attackers may target payment portals, donation systems, and merchant dashboards that store more than a single transaction. Defenders reduce risk by limiting what is collected, encrypting stored values, masking card numbers, enforcing strong access control, and avoiding retention of sensitive fields that are not required for payment processing.